Peterborough 0-2 Man City: Riyad Mahrez & Jack Grealish goals send Premier League leaders through

Jack Grealish says the first FA Cup goal of his career was inspired by watching footage of Lionel Messi before Manchester City's hard-earned win over Peterborough United.

Riyad Mahrez put the Premier League leaders ahead with their first attempt on target before Grealish - the most expensive British player of all time - sealed City's place in the quarter-finals.

The England midfielder produced a quality first touch to bring Phil Foden's sweeping pass from inside his own half under control before rolling it beyond the keeper and into the net.

"What's funny is that before the game, while we were on the coach on the way to the game, I was sat next to Phil and we were scrolling through videos of Messi," Grealish told ITV.

"After scoring [Foden] came up to me and said it was just like we were watching."

City were made to work hard for their fifth-round win.

Peterborough, bottom of the Championship, should have taken the lead with the game goalless but Sammie Szmodics scuffed his attempt, and Jeando Fuchs was denied by Ederson.

Six-time winners City will discover their opponents on Thursday.

• Ukraine defender Zinchenko captains Man City in FA Cup tie with Peterborough

• Reaction from Tuesday's FA Cup ties

Peterborough United are bottom of the Championship while Manchester City are top of the Premier League

Man City get the job done

City have now scored 103 goals in all competitions this season.

But it required two quality finishes - both assisted by Foden - in the space of seven second-half minutes to seal City's passage.

City made six changes but still fielded a strong side which included returning Ukraine defender Oleksandr Zinchenko, who was handed the captain's armband in a sign of solidarity and support.

It was Zinchenko's first game since his homeland was invaded by Russia and he held the Ukrainian flag on the pitch with Peterborough captain Frankie Kent before kick-off.

A message on the big screen read 'We Stand With Ukraine' and fans held up a banner which read 'Zinchenko: We Stand With You'.

Zinchenko, making his first start since 12 February, had a couple of early attempts but City's team of expensive signings and internationals failed to test keeper Steven Benda before Mahrez struck on the hour.

The Algeria winger had lots of work to do after receiving a pass from Foden but showed his quality by creating space for himself to break the deadlock before Grealish's finish confirmed City's place in the next round.

Mahrez is enjoying his best goalscoring season in English football, with his 19 goals one more than he scored in Leicester's 2015-16 title winning campaign.

"We know the quality Riyad has and he loves to play football," said City boss Pep Guardiola. "It's not a profession to him, it's a joy. He would play every single day."

City turn attention to the Manchester derby

Guardiola batted away questions about a possible treble after his side's fourth successive away win without conceding in three different competitions.

Six points clear of nearest rivals Liverpool at the top of the Premier League, albeit having played one more game, City are approaching the business end of the season in a familiar position.

They also have one foot in the Champions League quarter-finals after establishing a handsome 5-0 first-leg lead over Sporting Lisbon.

"I am not going to buy this argument," said Guardiola when asked about the prospect of ending the season with three trophies.

Next it is the Manchester derby at Etihad Stadium, where United have triumphed on their past three visits.

'I'm really proud of our performance'

Peterborough United boss Grant McCann, speaking to ITV: "I am really proud of our performance. Defensively we were well organised. And we had a massive chance to go 1-0 up.

"On another day we do, but when you play against a top-class team they keep probing and probing. I've said to the boys that this is the bench mark. There is a lot of quality in the dressing room."